Signaling and decoding of punctured subbands in trigger-based ppdu

ABSTRACT

In some aspects, the disclosure is directed to methods and systems for signaling and decoding of punctured sub-bands in a trigger-based PPDU. In one aspect, at least one of the communication interface or the processing circuitry of a wireless communication device is configured to generate a trigger frame that includes signaling indicating that at least one other wireless communication device is allowed to reduce a bandwidth of an allocated resource unit (RU) for transmitting data via a communication channel; transmit, via the communication channel, the trigger frame to at least one other wireless communication device; receive, via the communication channel and from the at least one other wireless communication device, an uplink (UL) orthogonal frequency division multiple access (OFDMA) frame including the data; and process the UL OFDMA frame including the data based on the signaling.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims the benefit of priority to U.S. application Ser.No. 17/170,139, filed Feb. 8, 2021, which claims the benefit of priorityto U.S. Provisional Patent Application No. 62/984,204, filed Mar. 2,2020, each of which is incorporated by reference in its entirety for allpurposes.

FIELD OF THE DISCLOSURE

This disclosure generally relates to systems and methods forcommunication systems. In particular, this disclosure relates to systemsand methods for signaling and communications within single user,multiple user, multiple access, and/or multiple-input-multiple-output(MIMO) wireless communications.

BACKGROUND OF THE DISCLOSURE

The Wi-Fi Standard 802.11be will support punctured 80 MHz, 160 MHz and320 MHz transmissions. Unlike previous 802.11 generations, a station(STA) that intends to transmit at a given bandwidth, e.g., 160 MHz, andfinds parts of that spectrum busy or disallowed can transmit onavailable portions, e.g., 80+40 MHz, and signal the exact transmissionbandwidth (BW) and location in the signaling (SIG) field. However, SIGfield-based signaling may be unavailable or not possible in someimplementations, preventing STAs from taking advantage of puncturedtransmissions.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, aspects, features, and advantages of the disclosurewill become more apparent and better understood by referring to thedetailed description taken in conjunction with the accompanyingdrawings, in which like reference characters identify correspondingelements throughout. In the drawings, like reference numbers generallyindicate identical, functionally similar, and/or structurally similarelements.

FIG. 1 is a diagram illustrating an example of a trigger-based signalexchange between wireless communication devices.

FIG. 2 is a diagram illustrating an example of a trigger frame for usein a trigger-based signal exchange between wireless communicationdevices.

FIG. 3 is a diagram illustrating an example of a UL data frame for usein a trigger-based signal exchange between wireless communicationdevices.

FIG. 4 is a diagram illustrating examples of 80 MHz RU segments, 160 MHzRU segments, and 320 MHz RU segments.

FIG. 5A is a diagram illustrating an example communication protocolindicating a BW reduction amount.

FIG. 5B is a diagram illustrating an example communication protocolindicating which one or more segments have their BW reduced for the casewhen the allocated RU is less than or equal to 80 MHz.

FIG. 5C is a diagram illustrating an example communication protocolindicating which one or more segments have their BW reduced for the casewhen the allocated RU is less than or equal to 160 MHz and greater than80 MHz.

FIG. 5D is a diagram illustrating an example communication protocolindicating which one or more segments have their BW reduced for the casewhen the allocated RU is less than or equal to 320 MHz and greater than160 MHz.

FIG. 6A is a diagram illustrating an embodiment of a method forexecution by one or more wireless communication devices.

FIG. 6B is a diagram illustrating an embodiment of a method forexecution by one or more wireless communication devices.

FIG. 7A is a block diagram depicting an embodiment of a networkenvironment including one or more access points in communication withone or more devices or stations; and

FIGS. 7B and 7C are block diagrams depicting embodiments of computingdevices useful in connection with the methods and systems describedherein.

The details of various embodiments of the methods and systems are setforth in the accompanying drawings and the description below.

DETAILED DESCRIPTION

The following IEEE standard(s), including any draft versions of suchstandard(s), are hereby incorporated herein by reference in theirentirety and are made part of the present disclosure for all purposes:IEEE P802.11n™; and IEEE P802.11ac™. Although this disclosure mayreference aspects of these standard(s), the disclosure is in no waylimited by these standard(s).

For purposes of reading the description of the various embodimentsbelow, the following descriptions of the sections of the specificationand their respective contents may be helpful:

-   -   Section A describes embodiments of systems and methods for        signaling and decoding punctured sidebands in a trigger-based        PPDU; and    -   Section B describes a network environment and computing        environment which may be useful for practicing embodiments        described herein.

A. Signaling and Decoding Punctured Sidebands in a Trigger-Based PPDU

The Wi-Fi Standard 802.11be may support punctured 80 MHz, 160 MHz and320 MHz transmissions. Unlike previous 802.11 generations, a station(STA) that intends to transmit, e.g., 160 MHz, and finds parts of thatspectrum busy or disallowed can transmit on portions, e.g., 80+40 MHz,and signal a transmission bandwidth (BW) and a location in a signaling(SIG) field. However, in a trigger based uplink (UL) orthogonalfrequency division multiple access (OFDMA) transmission, the STA may notbe able to signal the BW and the location in the SIG field as the accesspoint (AP) may determine the contents of the SIG field and instruct theSTA the BW and the location in which to transmit the UL OFDMA dataframe. It is, however, desirable to enable STA sending a trigger-basedUL OFDMA data frame to reduce its BW if some parts of its allocated BWare busy.

Some embodiments of the present disclosure enable blind detection by theAP in trigger based UL OFDMA. In some embodiments, the AP decodes the ULOFDMA data frame to determine if its BW has been reduced. In someembodiments, new fields are included in the trigger frame that set rulesfor how the STA can reduce its BW. Accordingly, the new fields may helpthe AP control its decoding complexity by reducing the number ofhypotheses the AP has to check to determine if a STA reduced its BW intransmitting the trigger based UL OFDMA data frame. Some embodiments ofthe present disclosure enable a STA to signal if the STA transmitted ona partial (e.g., smaller than allocated by the AP) BW. In someembodiments, new bits are included in signaling fields (e.g., U-SIG) inthe UL OFDMA data frame.

Various embodiments disclosed herein are directed to a wirelesscommunication device. In some embodiments, the wireless communicationdevice includes a communication interface and processing circuitry thatis coupled to the communication interface. In some embodiments, at leastone of the communication interface or the processing circuitry isconfigured to generate a trigger frame that includes signalingindicating that at least one other wireless communication device isallowed to reduce a bandwidth of an allocated resource unit (RU) fortransmitting data via a communication channel; transmit, via thecommunication channel, the trigger frame to at least one other wirelesscommunication device; receive, via the communication channel and fromthe at least one other wireless communication device, an uplink (UL)orthogonal frequency division multiple access (OFDMA) frame includingthe data; and process the UL OFDMA frame including the data based on thesignaling.

In some embodiments, the wireless communication device processes the ULOFDMA frame including the data without receiving, from the at least oneother wireless communication device, signaling indicating an amount forreduction of the bandwidth. In some embodiments, the UL OFDMA frameindicates whether the wireless communication device is reducing thebandwidth. In some embodiments, the at least one other wirelesscommunication device reduces the bandwidth based on determining that anamount of the bandwidth of the allocated RU includes interferencegreater than a predetermined threshold. In some embodiments, the triggerframe indicates one or more sub-band locations in which the bandwidth isallowed to be reduced. In some embodiments, the trigger frame indicatesa resolution with which the at least one other wireless communicationdevice is allowed to reduce the bandwidth. In some embodiments, thetrigger frame indicates a target received signal strength indicator(RSSI) based on the resolution. In some embodiments, at least one of thecommunication interface or the processing circuitry is furtherconfigured to receive, via the first communication channel and from asecond other wireless communication device, a second uplink (UL) OFDMAframe including second data and process the second UL OFDMA frameincluding the second data based on the signaling. In some embodiments,the wireless communication device is an access point (AP) and the atleast one other communication device is a station (STA).

Various embodiments disclosed herein are directed to a wirelesscommunication device. In some embodiments, the wireless communicationdevice includes a communication interface and processing circuitry thatis coupled to the communication interface. In some embodiments, at leastone of the communication interface or the processing circuitryconfigured to generate, in response to a trigger frame from a secondwireless communication device allocating a resource unit (RU) having afirst bandwidth, an uplink (UL) orthogonal frequency division multipleaccess (OFDMA) frame including data and transmit, to the second wirelesscommunication device, the UL OFDMA frame in a second bandwidth of theRU. In some embodiments, the second bandwidth is less than the firstbandwidth by an amount determined by the wireless communication device.In some embodiments, the UL OFDMA frame is to be processed to decode thedata.

In some embodiments, the method further includes determining whether athird bandwidth of the allocated RU includes interference greater than apredetermined threshold. In some embodiments, transmitting the UL OFDMAframe in the second bandwidth based on determining that the amount ofthe first bandwidth of the allocated RU includes the interferencegreater than the predetermined threshold. In some embodiments, the ULOFDMA frame does not include signaling that indicates that the wirelesscommunication device is reducing the first bandwidth to the secondbandwidth. In some embodiments, the UL OFDMA frame includes signalingthat indicates that the wireless communication device is reducing thefirst bandwidth to the second bandwidth. In some embodiments, the ULOFDMA frame indicates a resolution with which the wireless communicationdevice reduces the bandwidth. In some embodiments, the UL OFDMA frameindicates one or more sub-band locations in which the bandwidth isreduced by the amount. In some embodiments, the UL OFDMA frame indicatesa different packet extension identifier than a packet extensionidentifier indicated in the trigger frame. In some embodiments, the ULOFDMA frame indicates a different pre-forward error correcting (FEC)padding factor than an FEC padding factor indicated in the triggerframe. In some embodiments, the wireless communication device is astation (STA) and the second wireless communication device is an accesspoint (AP).

Various embodiments disclosed herein are directed to a method by awireless communication device. In some embodiments, the method includesgenerating, by processing circuitry of the wireless communicationdevice, a trigger frame that includes signaling indicating that at leastone other wireless communication device is allowed to reduce a bandwidthof an allocated resource unit (RU) for transmitting data via acommunication channel; transmitting, by a communication interface of thewireless communication device and via the communication channel, thetrigger frame to at least one other wireless communication device;receiving, by the communication interface and via the communicationchannel and from the at least one other wireless communication device,an uplink (UL) orthogonal frequency division multiple access (OFDMA)frame including the data; and processing, by the processing circuitry,the UL OFDMA frame including the data based on the signaling.

FIG. 1 is a diagram illustrating an example 100 of a trigger-basedsignal exchange between wireless communication devices. A centralcontroller (e.g., an AP, a central controller wireless device) isconfigured to generate a trigger frame (or other broadcasted frame),e.g., which may be an orthogonal frequency-division multiple access(OFDMA) frame, that specifies certain information. In some examples, thetrigger frame specifies (e.g., specifies, indicates, allocates) aplurality of resource units (RUs) to be used by respective wirelessdevices (e.g., STAs) when transmitting a second OFDMA frame to thewireless communication device.

The central controller may be configured to transmit the trigger frameto the wireless devices. One or more of the wireless devices may preparedata for transmission to the central controller after parsing theresource allocation information conveyed in the trigger frame anddiscovering a resource allocation allocated to itself. The wirelessdevices may transmit uplink (UL) data frames to the central controllerat the respective RUs indicated in the trigger frame. In someembodiments, the UL data frames are at least one of single-user (SU) ULdata frames and multi-user (MU) UL data frames.

FIG. 2 is a diagram illustrating an example 200 of a trigger frame foruse in a trigger-based signal exchange between wireless communicationdevices. In some embodiments, the Common information (info.) field ofthe trigger frame includes one or more of the following: a (e.g., 1 bit)BW Reduction Enable (BRE) field and/or a (e.g., 4 bit) BW ReductionSegment Enable (BRSE) field. The BRE may enable the AP to controlwhether BW reduction is permitted (e.g., allowed) at all on thesubsequent trigger-based (TB) physical layer convergence protocol (PLCP)protocol data unit (PPDU). Setting to “disallowed” may indicate that noSTA can reduce its BW. The BRSE field may be an n-bit mask to indicatewhich segments (e.g., sub-bands, portions of RUs, 80 MHz segments) theSTAs are allowed to reduce their BW if allocated in multiple segments(e.g., which segments are not used for transmitting the UL OFDMA dataframe, which segments are punctured). Alternatively, the BRSE field mayindicate which segments are transmitting the UL OFDMA data, such thatthe segments not indicated are the ones reducing their BW.

In some embodiments, the Per user info. field of the trigger frameincludes one or more of the following: a (e.g., 1 bit) per-user BREfield, a (e.g., 4 bit) per-user BRSE field, a (e.g., 1 bit) resolution(Res) field, or a per-20 MHz RSSI (RSSI20 MHz) field. The per-user BREfield may enable the AP to control which STA can reduce their BW. Theper-user BRSE field may indicate in which segments the STA is allowed toreduce its BW if it is allocated in multiple segments. The resolutionfield can indicate a resolution of the reduced BW. For example, theresolution field uses a 1 bit to signal 20 MHz or 40 MHz. For example,if the STA was allocated 80 MHz and the Resolution field signals 20 MHz,then the STA can reduce its BW to 20 MHz, 40 MHz, or 60 MHz in anylocation within its allotted 80 MHz, and if the Resolution field signals40 MHz then the STA can reduce its BW to 40 MHz in any location withinits allotted 80 MHz. The BRE, BRSE and resolution fields can reducehypotheses checking by AP. The RSSI20 MHz field can signal the UL targetRSSI per 20 MHz. The RSSI20 MHz field may be used because if the STAreduces its transmit BW, then the same target RSSI at the AP translatesto a higher power-spectral density (PSD), which can impede the AP'sreception of other STAs' signals.

FIG. 3 is a diagram illustrating an example of a UL frame (e.g., UL dataframe, UL OFDMA frame) 300 for use in a trigger-based signal exchangebetween wireless communication devices. In some embodiments, the ULframe includes multiple 20 MHz portions. Each 20 MHz portion includes adata field and a signaling (SIG) field (e.g., a universally signaling(U-SIG) field or a SIG-A field). In some embodiments, each 20 MHzportion is transmitted by a different STA to the AP. In someembodiments, at least two 20 MHz portions are transmitted by a same STAto the AP.

In some embodiments, each STA determines a BW reduction amount (e.g., aresolution) and a location (e.g., a sub-band) of the BW reducedsegments. In some embodiments, each STA maps the BW reduction amount andthe location of the BW reduced segments to bits in the U-SIG field ofthe UL OFDMA frame to be transmitted. In other words, the bit-mapping inthe U-SIG may be performed per each STA that is transmitting the ULOFDMA frame. The U-SIG field signals (e.g., indicates) if a STAtransmits on a partial BW, smaller than allocated by the AP. In someembodiments, the U-SIG includes a (e.g., 2 bit) BW reduction (BR) field.In some embodiments, the BR field indicates an amount of BW that thecorresponding STA is reduced by.

In some embodiments, the U-SIG includes a (e.g., 3 bit) BW ReductionSegment (BRS) field. In some embodiments, the BRS field indicates whichone or more segments have their BW reduced.

Referring now to FIG. 4 , illustrated is a diagram of example 400A of 80MHz RU segments, example 400B of 160 MHz RU segments, and example 400Cof 320 MHz RU segments. The first variable (e.g., L or U) indicates alower-half (or higher-half) of the RU, and the second variable indicatesa lower-half (or higher-half) of the segment identified by the first.For example, the first 20 MHz segment of the 80 MHz RU of 400A can bereferred to as “20LL,” the first 20 MHz segment of the 80 MHz RU of 400Acan be referred to as “20LU,” the third 20 MHz segment of the 80 MHz RUof 400A can be referred to as “20UL,” the fourth 20 MHz segment of the80 MHz RU of 400A can be referred to as “20UU,”

Referring to FIG. 5A, illustrated is a diagram of an examplecommunication protocol 500A for the BR field indicating a BW reductionamount. The example protocol 500A maps a RU BW and the BR bits to a BWreduction amount. For example, if the allocated RU (e.g., the BW) is 80MHz or less and (a) the BR bits are ‘00,’ then the BW of the allocatedRU is not reduced, (b) the BR bits are ‘01,’ then the BW of theallocated RU is reduced by 20 MHz, or (c) the BR bits are ‘10,’ then theBW of the allocated RU may be reduced by 40 MHz.

If the allocated RU exceeds 80 MHz, the allocated RU does not exceed 160MHz, and (a) the BR bits are ‘00,’ then the BW of the allocated RU maynot reduced (b) the BR bits are ‘01,’ then the BW of the allocated RUmay be reduced by 20 MHz, (c) the BR bits are ‘10,’ then the BW of theallocated RU may be reduced by 40 MHz, or (d) the BR bits are ‘11,’ thenthe BW of the allocated RU may be reduced by 80 MHz. If the allocated RUexceeds 160 MHz, the allocated RU does not exceed 320 MHz, and (a) theBR bits are ‘00,’ then the BW of the allocated RU may not reduced (b)the BR bits are ‘01,’ then the BW of the allocated RU may be reduced by40 MHz, (c) the BR bits are ‘10,’ then the BW of the allocated RU may bereduced by 80 MHz, or (d) the BR bits are ‘11,’ then the BW of theallocated RU may be reduced by 160 MHz. In other implementations,various other encodings of BW reduction to BR bits may be utilized.

FIG. 5B is a diagram illustrating example protocol 500B indicating whichone or more segments have their BW reduced for the case when theallocated RU is less than or equal to 80 MHz. The example protocol 500Bmaps the BR bits and the BRS bits to a BW reduction segment. Forexample, if the BR bits are ‘01’ (e.g., indicating that the BW reductionamount is 20 MHz) and (a) the BRS bits are ‘00x,’ then the segment inwhich the BW is reduced is 20LL, (b) the BRS bits are ‘01x,’ then thesegment in which BW is reduced is 20LU, (c) the BRS bits are ‘10x,’ thenthe segment in which the BW is reduced is 20UL, or (d) the BRS bits are‘11x,’ then the segment in which BW is reduced is 20UU.

If the BR bits are ‘10’ and (a) the BRS bits are ‘000,’ then the segmentin which BW is reduced is 40L, or (b) the BRS bits are ‘001,’ then thesegment in which BW is reduced is 40U. In some embodiments, the segmentsin which the BW is reduced are not contiguous. For example, if the BRbits are ‘10’ and (a) the BRS bits are ‘010,’ then the segments in whichBW is reduced are 20LU+20UL, (a) the BRS bits are ‘011,’ then thesegments in which BW is reduced are 20UU+20LL, (a) the BRS bits are‘101,’ then the segments in which BW is reduced are 20LL+20UL, (a) theBRS bits are ‘111,’ then the segments in which BW is reduced are20LU+20UU. In other implementations, various other encodings of BWreduction to BR bits may be utilized.

FIG. 5C is a diagram illustrating example protocol 500C indicating whichone or more segments have their BW reduced for the case when theallocated RU is less than or equal to 160 MHz and greater than 80 MHz.For example, if the BR bits are ‘01’ and (a) the BRS bits are ‘000,’then the segment in which BW is reduced is 20LLL, (b) the BRS bits are‘001,’ then the segment in which BW is reduced is 20LLU, (c) the BRSbits are ‘010’ then the segment in which BW is reduced is 20LUL, (d) theBRS bits are ‘011,’ then the segment in which BW is reduced is 20LUU,(e) the BRS bits are ‘100,’ then the segment in which BW is reduced is20ULL, (f) the BRS bits are ‘101,’ then the segment in which BW isreduced is 20ULU, (g) the BRS bits are ‘110,’ then the segment in whichBW is reduced is 20UUL, or (h) the BRS bits are ‘111,’ then the segmentin which BW is reduced is 20UUU.

If the BR bits are ‘10’ and (a) the BRS bits are ‘000,’ then the segmentin which BW may be reduced is 40LL, (b) the BRS bits are ‘001,’ then thesegment in which BW may be reduced is 40LU, (c) the BRS bits are ‘010’the segment in which BW may be reduced is 40UL, (d) the BRS bits are‘011,’ then the segment in which BW may be reduced is 40UU, (e) the BRSbits are ‘100,’ then the segments in which BW may be reduced are20LLU+20LUL, (f) the BRS bits are ‘101,’ then the segments in which BWmay be reduced are 20LUU+20ULL, (g) the BRS bits are ‘110,’ then thesegments in which BW may be reduced are 20ULU+20UUL, or (h) the BRS bitsare ‘111,’ then the segments in which BW may be reduced are 20UUU+20LLL.

If the BR bits are ‘11’ and (a) the BRS bits are ‘000,’ then the segmentin which BW may be reduced is 80L, (b) the BRS bits are ‘001,’ then thesegment in which BW may be reduced is 80U, (c) the BRS bits are ‘010,’then the segments in which BW may be reduced are 40LU+40UL, (d) the BRSbits are ‘011,’ then the segments in which BW may be reduced are40UU+40LL, (e) the BRS bits are ‘100,’ then the segments in which BW maybe reduced are 40LL+40UL, or (f) the BRS bits are ‘101,’ then thesegments in which BW may be reduced are 40LU+40UU. In otherimplementations, various other encodings of BW reduction to BR bits maybe utilized.

FIG. 5D is a diagram illustrating example protocol 500D indicating whichone or more segments have their BW reduced for the case when theallocated RU is less than or equal to 320 MHz and greater than 160 MHz.For example, if the BR bits are ‘01’ and (a) the BRS bits are ‘000,’then the segment in which BW is reduced is 40LLL, (b) the BRS bits are‘001,’ then the segment in which BW is reduced is 40LLU, (c) the BRSbits are ‘010’ then the segment in which BW is reduced is 40LUL, (d) theBRS bits are ‘011,’ then the segment in which BW is reduced is 40LUU,(e) the BRS bits are ‘100,’ then the segment in which BW is reduced is40ULL, (f) the BRS bits are ‘101,’ then the segment in which BW isreduced is 40ULU, (g) the BRS bits are ‘110,’ then the segment in whichBW is reduced is 40UUL, or (h) the BRS bits are ‘111,’ then the segmentin which BW is reduced is 40UUU.

If the BR bits are ‘10’ and (a) the BRS bits are ‘000,’ then the segmentin which BW may be reduced is 80LL, (b) the BRS bits are ‘001,’ then thesegment in which BW may be reduced is 80LU, (c) the BRS bits are ‘010’the segment in which BW may be reduced is 80UL, (d) the BRS bits are‘011,’ then the segment in which BW may be reduced is 80UU, (e) the BRSbits are ‘100,’ then the segments in which BW may be reduced are40LLU+40LUL, (f) the BRS bits are ‘101,’ then the segments in which BWmay be reduced are 40LUU+40ULL, (g) the BRS bits are ‘110,’ then thesegments in which BW may be reduced are 40ULU+40UUL, or (h) the BRS bitsare ‘111,’ then the segments in which BW may be reduced are 40UUU+40LLL.

If the BR bits are ‘11’ and (a) the BRS bits are ‘000,’ then the segmentin which BW may be reduced is 160L, (b) the BRS bits are ‘001,’ then thesegment in which BW may be reduced is 160U, (c) the BRS bits are ‘010,’then the segments in which BW may be reduced are 80LU+80UL, (d) the BRSbits are ‘011,’ then the segments in which BW may be reduced are80UU+80LL, (e) the BRS bits are ‘100,’ then the segments in which BW maybe reduced are 80LL+80UL, or (f) the BRS bits are ‘101,’ then thesegments in which BW may be reduced are 80LU+80UU. In otherimplementations, various other encodings of BW reduction to BR bits maybe utilized.

The triggered STA may signal information to the AP to indicate one ormore updated PPDU parameters in the trigger based (TB) PPDU. In someembodiments, a signaling bit is used to signal a different packetextension disambiguity (e.g., identifier) in the PPDU than what wasindicated in the trigger message. In some embodiments, a signaling bitsignals a different pre-FEC padding factor than what was indicated inthe trigger message. A signaling bit may signal if the PPDU encodingprocess with low-density parity-check (LDPC) with the reduced BWresulted has an extra OFDM symbol. Signaling bits may signal if themodulation and coding scheme used in the TB PPDU. Signaling bits maysignal if dual carrier modulation (DCM) is employed in the TB PPDU. Asignaling bit may signal if the forward error correcting (FEC) type haschanged. Signaling bits may be used to signal the starting spatialstream and the number of spatial streams. The TB PPDU parameters may bemodified and signaled regardless of bandwidth reduction. In someembodiments, the signaling bits are included in the U-SIG.

FIG. 6A is a diagram illustrating an embodiment of a method 600 forexecution by one or more wireless communication devices. Additional,fewer, or different operations may be performed in the method 600depending on the embodiment.

At operation 602, a first wireless communication device (e.g., an AP)may generate a first frame that indicates that at least one otherwireless communication device (e.g., a STA) is allowed to reducebandwidth in an allocated resource unit (RU) for transmitting data in asecond frame via a communication channel (e.g., by an amount determinedby the at least one other wireless communication device). In someembodiments, the first wireless communication device indicates anallowed resolution and allowed locations of the reduced bandwidth (e.g.,segments/sub-bands in the allocated RU that are not used fortransmitting the second frame, segments/sub-bands that are punctured).The first frame can be a orthogonal frequency division multiple access(OFDMA) frame. In some embodiments, the first frame is a trigger frame.

At operation 604, the first wireless communication device may transmitthe first frame. The first frame can be transmitted via thecommunication channel. The first frame is transmitted to the at leastone other wireless communication device to be processed by the at leastone other wireless communication device to determine whether to reducethe bandwidth in the allocated RU. In some embodiments, the first frameis broadcasted to multiple wireless communication devices.

At operation 606, the at least one other wireless communication devicemay generate the second frame that indicates one or more of whether theother wireless communication device is reducing its BW for transmittingthe data, an amount by which the other wireless communication device isreducing its BW, or a location of the reduced bandwidth within theallocated RU. The second frame can be an orthogonal frequency divisionmultiple access (OFDMA) frame. In some embodiments, the second frame isan uplink (UL) frame (e.g., a UL OFDMA frame) that includes the data tobe transmitted.

At operation 608, the other wireless communication device transmits thesecond frame. In some embodiments, the second frame is transmitted inthe allocated RU having the reduced BW. Thus, for example, if the otherwireless communication device indicates that the location of the reducedBW of a 80 MHz RU is the 20LL segment, the other wireless communicationdevice transmits the second frame in the 20LU+40U segments. In someembodiments, multiple wireless communication devices send second framesat the same time (or at approximately the same time, or, in someimplementations, in series) to the first wireless communication deviceas part of a MU UL frame. Accordingly, operations 606-608 may beperformed by a plurality of other wireless communication devicessimultaneously.

At operation 610, the first wireless communication device processes thesecond frame to determine whether the at least one other wirelesscommunication device is reducing its BW and the location of the reducedbandwidth within the allocated RU.

FIG. 6B is a diagram illustrating an embodiment of a method 650 forexecution by one or more wireless communication devices. Additional,fewer, or different operations may be performed in the method 650depending on the embodiment.

Operations 602 and 604 may be the same as or similar to the operations602 and 604 of the method 600. At operation 656, the wireless device(e.g., an AP) receives, from another wireless device (e.g., a STA), asecond frame including data. In some embodiments, the second frame is anuplink (UL) frame (e.g., a UL OFDMA frame). In some embodiments, thesecond frame does not include an indication of whether the anotherwireless device reduced the BW.

At operation 658, the wireless device determines whether the BW isreduced. In some embodiments, the wireless device determines whether theBW is reduced in accordance with the signaling in the first frame. Forexample, if the first frame indicates that the BW can only be reduced in40 MHz segments, the wireless device determines whether BW is reduced in40 MHz segments. In some embodiments, the wireless device processes eachsegment to determine if signaling (e.g., a header, a field, anidentifier, pre-determined signaling) is identified. In someembodiments, if the wireless device determines that signaling is notidentified in at least one segment, the wireless device determines thatthe BW is reduced.

In response to determining that the BW is reduced, at operation 660, thewireless device processes the second frame to determine the location ofthe reduced BW. At operation 662, the wireless device processes thesecond frame to decode the data. In response to determining that the BWis not reduced, at operation 660, the wireless device bypasses operation660 and proceeds at operation 662.

Accordingly, the systems and methods discussed herein provide forsignaling and decoding of punctured subbands in a trigger-based PPDU. Inone aspect, at least one of the communication interface or theprocessing circuitry of a wireless communication device (e.g., an AP) isconfigured to generate trigger frame that indicates signaling that atleast one other wireless communication device is allowed to reducebandwidth in an allocated resource unit (RU) for transmitting data via acommunication channel, transmit, via the communication channel, thetrigger frame to at least one other wireless communication device,receive, via the communication channel and from the at least one otherwireless communication device, an uplink (UL) OFDMA frame including thedata, and process the UL OFDMA frame including the data based on thesignaling.

In another aspect, at least one of the communication interface or theprocessing circuitry of a wireless communication (e.g., a STA) device isconfigured to generate an uplink (UL) OFDMA frame indicating whether thewireless communication device is reducing its BW in an allocatedresource unit (RU) for transmitting data via a communication channel anda location of the reduced bandwidth within the allocated RU, andtransmit, to a second wireless communication device, the UL OFDMA frameto be processed to determine whether the wireless communication deviceis reducing its BW and the location of the reduced bandwidth within theallocated RU. In some embodiments, at least one of the communicationinterface or the processing circuitry configured to receiving a triggerframe from the second wireless communication device. In someembodiments, the trigger frame indicates signaling that the wirelesscommunication device is allowed to reduce bandwidth in the allocated RUfor transmitting data via a communication channel.

B. Computing and Network Environment

Having discussed specific embodiments of the present solution, it may behelpful to describe aspects of the operating environment as well asassociated system components (e.g., hardware elements) in connectionwith the methods and systems described herein. Referring to FIG. 7A, anembodiment of a network environment is depicted. In brief overview, thenetwork environment includes a wireless communication system thatincludes one or more access points 706, one or more wirelesscommunication devices 702 and a network hardware component 792. Thewireless communication devices 702 may for example include laptopcomputers 702, tablets 702, personal computers 702 and/or cellulartelephone devices 702. The details of an embodiment of each wirelesscommunication device and/or access point are described in greater detailwith reference to FIGS. 7B and 7C. The network environment can be an adhoc network environment, an infrastructure wireless network environment,a subnet environment, etc. in one embodiment.

The access points (APs) 706 may be operably coupled to the networkhardware 792 via local area network connections. The network hardware792, which may include a router, gateway, switch, bridge, modem, systemcontroller, appliance, etc., may provide a local area network connectionfor the communication system. Each of the access points 706 may have anassociated antenna or an antenna array to communicate with the wirelesscommunication devices 702 in its area. The wireless communicationdevices 702 may register with a particular access point 706 to receiveservices from the communication system (e.g., via a SU-MIMO or MU-MIMOconfiguration). For direct connections (e.g., point-to-pointcommunications), some wireless communication devices 702 may communicatedirectly via an allocated channel and communications protocol. Some ofthe wireless communication devices 702 may be mobile or relativelystatic with respect to the access point 706.

In some embodiments an access point 706 includes a device or module(including a combination of hardware and software) that allows wirelesscommunication devices 702 to connect to a wired network using Wi-Fi, orother standards. An access point 706 may sometimes be referred to as anwireless access point (WAP). An access point 706 may be configured,designed and/or built for operating in a wireless local area network(WLAN). An access point 706 may connect to a router (e.g., via a wirednetwork) as a standalone device in some embodiments. In otherembodiments, an access point can be a component of a router. An accesspoint 706 can provide multiple devices 702 access to a network. Anaccess point 706 may, for example, connect to a wired Ethernetconnection and provide wireless connections using radio frequency linksfor other devices 702 to utilize that wired connection. An access point706 may be built and/or configured to support a standard for sending andreceiving data using one or more radio frequencies. Those standards, andthe frequencies they use may be defined by the IEEE (e.g., IEEE 802.11standards). An access point may be configured and/or used to supportpublic Internet hotspots, and/or on an internal network to extend thenetwork's Wi-Fi signal range.

In some embodiments, the access points 706 may be used for (e.g.,in-home or in-building) wireless networks (e.g., IEEE 802.11, Bluetooth,ZigBee, any other type of radio frequency based network protocol and/orvariations thereof). Each of the wireless communication devices 702 mayinclude a built-in radio and/or is coupled to a radio. Such wirelesscommunication devices 702 and/or access points 706 may operate inaccordance with the various aspects of the disclosure as presentedherein to enhance performance, reduce costs and/or size, and/or enhancebroadband applications. Each wireless communication devices 702 may havethe capacity to function as a client node seeking access to resources(e.g., data, and connection to networked nodes such as servers) via oneor more access points 706.

The network connections may include any type and/or form of network andmay include any of the following: a point-to-point network, a broadcastnetwork, a telecommunications network, a data communication network, acomputer network. The topology of the network may be a bus, star, orring network topology. The network may be of any such network topologyas known to those ordinarily skilled in the art capable of supportingthe operations described herein. In some embodiments, different types ofdata may be transmitted via different protocols. In other embodiments,the same types of data may be transmitted via different protocols.

The communications device(s) 702 and access point(s) 706 may be deployedas and/or executed on any type and form of computing device, such as acomputer, network device or appliance capable of communicating on anytype and form of network and performing the operations described herein.FIGS. 7B and 7C depict block diagrams of a computing device 700 usefulfor practicing an embodiment of the wireless communication devices 702or the access point 706. As shown in FIGS. 7B and 7C, each computingdevice 700 includes a central processing unit 721, and a main memoryunit 722. As shown in FIG. 7B, a computing device 700 may include astorage device 728, an installation device 716, a network interface 718,an I/O controller 723, display devices 724 a-724 n, a keyboard 726 and apointing device 727, such as a mouse. The storage device 728 mayinclude, without limitation, an operating system and/or software. Asshown in FIG. 7C, each computing device 700 may also include additionaloptional elements, such as a memory port 703, a bridge 770, one or moreinput/output devices 730 a-730 n (generally referred to using referencenumeral 730), and a cache memory 740 in communication with the centralprocessing unit 721.

The central processing unit 721 is any logic circuitry that responds toand processes instructions fetched from the main memory unit 722. Inmany embodiments, the central processing unit 721 is provided by amicroprocessor unit, such as: those manufactured by Intel Corporation ofMountain View, California; those manufactured by International BusinessMachines of White Plains, New York; or those manufactured by AdvancedMicro Devices of Sunnyvale, California. The computing device 700 may bebased on any of these processors, or any other processor capable ofoperating as described herein.

Main memory unit 722 may be one or more memory chips capable of storingdata and allowing any storage location to be directly accessed by themicroprocessor 721, such as any type or variant of Static random accessmemory (SRAM), Dynamic random access memory (DRAM), Ferroelectric RAM(FRAM), NAND Flash, NOR Flash and Solid State Drives (SSD). The mainmemory 722 may be based on any of the above described memory chips, orany other available memory chips capable of operating as describedherein. In the embodiment shown in FIG. 7B, the processor 721communicates with main memory 722 via a system bus 750 (described inmore detail below). FIG. 7C depicts an embodiment of a computing device700 in which the processor communicates directly with main memory 722via a memory port 703. For example, in FIG. 7C the main memory 722 maybe DRDRAM.

FIG. 7C depicts an embodiment in which the main processor 721communicates directly with cache memory 740 via a secondary bus,sometimes referred to as a backside bus. In other embodiments, the mainprocessor 721 communicates with cache memory 740 using the system bus750. Cache memory 740 typically has a faster response time than mainmemory 722 and is provided by, for example, SRAM, BSRAM, or EDRAM. Inthe embodiment shown in FIG. 7C, the processor 721 communicates withvarious I/O devices 730 via a local system bus 750. Various buses may beused to connect the central processing unit 721 to any of the I/Odevices 730, for example, a VESA VL bus, an ISA bus, an EISA bus, aMicroChannel Architecture (MCA) bus, a PCI bus, a PCI-X bus, aPCI-Express bus, or a NuBus. For embodiments in which the I/O device isa video display 724, the processor 721 may use an Advanced Graphics Port(AGP) to communicate with the display 724. FIG. 7C depicts an embodimentof a computer 700 in which the main processor 721 may communicatedirectly with I/O device 730 b, for example via HYPERTRANSPORT, RAPIDIO,or INFINIBAND communications technology. FIG. 7C also depicts anembodiment in which local busses and direct communication are mixed: theprocessor 721 communicates with I/O device 730 a using a localinterconnect bus while communicating with I/O device 730 b directly.

A wide variety of I/O devices 730 a-730 n may be present in thecomputing device 700. Input devices include keyboards, mice, trackpads,trackballs, microphones, dials, touch pads, touch screen, and drawingtablets. Output devices include video displays, speakers, inkjetprinters, laser printers, projectors and dye-sublimation printers. TheI/O devices may be controlled by an I/O controller 723 as shown in FIG.7B. The I/O controller may control one or more I/O devices such as akeyboard 726 and a pointing device 727, e.g., a mouse or optical pen.Furthermore, an I/O device may also provide storage and/or aninstallation medium 716 for the computing device 700. In still otherembodiments, the computing device 700 may provide USB connections (notshown) to receive handheld USB storage devices such as the USB FlashDrive line of devices manufactured by Twintech Industry, Inc. of LosAlamitos, California.

Referring again to FIG. 7B, the computing device 700 may support anysuitable installation device 716, such as a disk drive, a CD-ROM drive,a CD-R/RW drive, a DVD-ROM drive, a flash memory drive, tape drives ofvarious formats, USB device, hard-drive, a network interface, or anyother device suitable for installing software and programs. Thecomputing device 700 may further include a storage device, such as oneor more hard disk drives or redundant arrays of independent disks, forstoring an operating system and other related software, and for storingapplication software programs such as any program or software 720 forimplementing (e.g., configured and/or designed for) the systems andmethods described herein. Optionally, any of the installation devices716 could also be used as the storage device. Additionally, theoperating system and the software can be run from a bootable medium.

Furthermore, the computing device 700 may include a network interface718 to interface to the network 704 through a variety of connectionsincluding, but not limited to, standard telephone lines, LAN or WANlinks (e.g., 802.11, T1, T3, 56 kb, X.25, SNA, DECNET), broadbandconnections (e.g., ISDN, Frame Relay, ATM, Gigabit Ethernet,Ethernet-over-SONET), wireless connections, or some combination of anyor all of the above. Connections can be established using a variety ofcommunication protocols (e.g., TCP/IP, IPX, SPX, NetBIOS, Ethernet,ARCNET, SONET, SDH, Fiber Distributed Data Interface (FDDI), RS232, IEEE802.11, IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, IEEE802.11ac, IEEE 802.11ad, CDMA, GSM, WiMax and direct asynchronousconnections). In one embodiment, the computing device 700 communicateswith other computing devices 700′ via any type and/or form of gateway ortunneling protocol such as Secure Socket Layer (SSL) or Transport LayerSecurity (TLS). The network interface 718 may include a built-in networkadapter, network interface card, PCMCIA network card, card bus networkadapter, wireless network adapter, USB network adapter, modem or anyother device suitable for interfacing the computing device 700 to anytype of network capable of communication and performing the operationsdescribed herein.

In some embodiments, the computing device 700 may include or beconnected to one or more display devices 724 a-724 n. As such, any ofthe I/O devices 730 a-730 n and/or the I/O controller 723 may includeany type and/or form of suitable hardware, software, or combination ofhardware and software to support, enable or provide for the connectionand use of the display device(s) 724 a-724 n by the computing device700. For example, the computing device 700 may include any type and/orform of video adapter, video card, driver, and/or library to interface,communicate, connect or otherwise use the display device(s) 724 a-724 n.In one embodiment, a video adapter may include multiple connectors tointerface to the display device(s) 724 a-724 n. In other embodiments,the computing device 700 may include multiple video adapters, with eachvideo adapter connected to the display device(s) 724 a-724 n. In someembodiments, any portion of the operating system of the computing device700 may be configured for using multiple displays 724 a-724 n. Oneordinarily skilled in the art will recognize and appreciate the variousways and embodiments that a computing device 700 may be configured tohave one or more display devices 724 a-724 n.

In further embodiments, an I/O device 730 may be a bridge between thesystem bus 750 and an external communication bus, such as a USB bus, anApple Desktop Bus, an RS-232 serial connection, a SCSI bus, a FireWirebus, a FireWire 800 bus, an Ethernet bus, an AppleTalk bus, a GigabitEthernet bus, an Asynchronous Transfer Mode bus, a FibreChannel bus, aSerial Attached small computer system interface bus, a USB connection,or a HDMI bus.

A computing device 700 of the sort depicted in FIGS. 7B and 7C mayoperate under the control of an operating system, which controlscheduling of tasks and access to system resources. The computing device700 can be running any operating system such as any of the versions ofthe MICROSOFT WINDOWS operating systems, the different releases of theUnix and Linux operating systems, any version of the MAC OS forMacintosh computers, any embedded operating system, any real-timeoperating system, any open source operating system, any proprietaryoperating system, any operating systems for mobile computing devices, orany other operating system capable of running on the computing deviceand performing the operations described herein. Typical operatingsystems include, but are not limited to: Android, produced by GoogleInc.; WINDOWS 7 and 8, produced by Microsoft Corporation of Redmond,Washington; MAC OS, produced by Apple Computer of Cupertino, California;WebOS, produced by Research In Motion (RIM); OS/2, produced byInternational Business Machines of Armonk, New York; and Linux, afreely-available operating system distributed by Caldera Corp. of SaltLake City, Utah, or any type and/or form of a Unix operating system,among others.

The computer system 700 can be any workstation, telephone, desktopcomputer, laptop or notebook computer, server, handheld computer, mobiletelephone or other portable telecommunications device, media playingdevice, a gaming system, mobile computing device, or any other typeand/or form of computing, telecommunications or media device that iscapable of communication. The computer system 700 has sufficientprocessor power and memory capacity to perform the operations describedherein.

In some embodiments, the computing device 700 may have differentprocessors, operating systems, and input devices consistent with thedevice. For example, in one embodiment, the computing device 700 is asmart phone, mobile device, tablet or personal digital assistant. Instill other embodiments, the computing device 700 is an Android-basedmobile device, an iPhone smart phone manufactured by Apple Computer ofCupertino, California, or a Blackberry or WebOS-based handheld device orsmart phone, such as the devices manufactured by Research In MotionLimited. Moreover, the computing device 700 can be any workstation,desktop computer, laptop or notebook computer, server, handheldcomputer, mobile telephone, any other computer, or other form ofcomputing or telecommunications device that is capable of communicationand that has sufficient processor power and memory capacity to performthe operations described herein.

Although the disclosure may reference one or more “users”, such “users”may refer to user-associated devices or stations (STAs), for example,consistent with the terms “user” and “multi-user” typically used in thecontext of a multi-user multiple-input and multiple-output (MU-MIMO)environment.

Although examples of communications systems described above may includedevices and APs operating according to an 802.11 standard, it should beunderstood that embodiments of the systems and methods described canoperate according to other standards and use wireless communicationsdevices other than devices configured as devices and APs. For example,multiple-unit communication interfaces associated with cellularnetworks, satellite communications, vehicle communication networks, andother non-802.11 wireless networks can utilize the systems and methodsdescribed herein to achieve improved overall capacity and/or linkquality without departing from the scope of the systems and methodsdescribed herein.

It should be noted that certain passages of this disclosure mayreference terms such as “first” and “second” in connection with devices,mode of operation, transmit chains, antennas, etc., for purposes ofidentifying or differentiating one from another or from others. Theseterms are not intended to merely relate entities (e.g., a first deviceand a second device) temporally or according to a sequence, although insome cases, these entities may include such a relationship. Nor do theseterms limit the number of possible entities (e.g., devices) that mayoperate within a system or environment.

It should be understood that the systems described above may providemultiple ones of any or each of those components and these componentsmay be provided on either a standalone machine or, in some embodiments,on multiple machines in a distributed system. In addition, the systemsand methods described above may be provided as one or morecomputer-readable programs or executable instructions embodied on or inone or more articles of manufacture. The article of manufacture may be afloppy disk, a hard disk, a CD-ROM, a flash memory card, a PROM, a RAM,a ROM, or a magnetic tape. In general, the computer-readable programsmay be implemented in any programming language, such as LISP, PERL, C,C++, C #, PROLOG, or in any byte code language such as JAVA. Thesoftware programs or executable instructions may be stored on or in oneor more articles of manufacture as object code.

While the foregoing written description of the methods and systemsenables one of ordinary skill to make and use what is consideredpresently to be the best mode thereof, those of ordinary skill willunderstand and appreciate the existence of variations, combinations, andequivalents of the specific embodiment, method, and examples herein. Thepresent methods and systems should therefore not be limited by the abovedescribed embodiments, methods, and examples, but by all embodiments andmethods within the scope and spirit of the disclosure.

What is claimed is:
 1. A device comprising: a communication interface;and processing circuitry that is coupled to the communication interface,wherein at least one of the communication interface or the processingcircuitry is configured to: generate a trigger frame comprising a fieldhaving a value indicating a resolution with which at least one otherdevice is allowed to reduce a bandwidth of an allocated resource unit(RU) for transmitting data via a communication channel; and transmit,via the communication channel, the trigger frame to the at least oneother device, wherein the at least one other device is configured totransmit a second frame according to the value in the field indicatingthe resolution with which the at least one other device is allowed toreduce the bandwidth.
 2. The device of claim 1, wherein the second frameis an uplink (UL) orthogonal frequency division multiple access (OFDMA)frame.
 3. The device of claim 2, wherein the UL OFDMA frame comprisesthe data.
 4. The device of claim 1, wherein at least one of thecommunication interface or the processing circuitry is configured to:receive, via the communication channel and from the at least one otherdevice, an uplink (UL) orthogonal frequency division multiple access(OFDMA) frame including the data; and process the UL OFDMA frameincluding the data.
 5. The device of claim 4, wherein UL OFDMA frameincludes a second value indicating an amount by which the bandwidth isreduced.
 6. The device of claim 1, wherein the at least one other devicereduces the bandwidth according to the value in the field responsive todetermining that an amount of the bandwidth of the allocated RU includesinterference greater than a predetermined threshold.
 7. The device ofclaim 1, wherein the trigger frame indicates one or more sub-bandlocations in which the bandwidth is allowed to be reduced.
 8. The deviceof claim 1, wherein the trigger frame comprises a second value thatindicates a target received signal strength indicator (RSSI) based onthe resolution.
 9. The device of claim 1, wherein the device is anaccess point (AP) and the at least one other communication device is astation (STA).
 10. The device, of claim 1, wherein the value indicatingthe resolution with which the at least one other device is allowed toreduce the bandwidth of the allocated RU for transmitting the data viathe communication channel is a single bit value.
 11. A device,comprising: a communication interface; and processing circuitry that iscoupled to the communication interface, wherein at least one of thecommunication interface or the processing circuitry is configured to:generate, in response to a trigger frame from a second device allocatinga resource unit (RU) having a first bandwidth, an uplink (UL) orthogonalfrequency division multiple access (OFDMA) frame including data, thetrigger frame comprising a field having a value indicating a resolutionwith which at least one other device is allowed to reduce a bandwidth ofthe allocated RU for transmitting the data via a communication channel;and transmit, based on the value indicating the resolution with which atleast one other device is allowed to reduce the bandwidth of theallocated RU for transmitting the data via the communication channel,the UL OFDMA frame in a second bandwidth of the RU, wherein the secondbandwidth is less than the first bandwidth by the value.
 12. The deviceof claim 11, wherein the at least one of the communication interface orthe processing circuitry is further configured to: determine whether athird bandwidth of the allocated RU includes interference greater than apredetermined threshold.
 13. The device of claim 12, wherein at leastone of the communication interface or the processing circuitry isfurther configured to transmit the UL OFDMA frame in the secondbandwidth based on determining that an amount of the first bandwidth ofthe allocated RU includes the interference greater than thepredetermined threshold.
 14. The device of claim 11, wherein the ULOFDMA frame indicates a different packet extension identifier than apacket extension identifier indicated in the trigger frame.
 15. Thedevice of claim 11, wherein the UL OFDMA frame indicates a differentpre-forward error correcting (FEC) padding factor than an FEC paddingfactor indicated in the trigger frame.
 16. The device of claim 11,wherein the device is a station (STA) and the second device is an accesspoint (AP).
 17. The device of claim 11, wherein the UL OFDMA frame oranother UL OFDMA frame is transmitted with one or more of (a) adifferent modulation and coding scheme (MCS) than an MCS indicated inthe trigger frame, or (b) a different number of spatial streams (NSS)than an NSS indicated in the trigger frame.
 18. A circuitry comprising:a communication interface; and a processor that is coupled to thecommunication interface, wherein at least one of the communicationinterface or the processing circuitry is configured to: generate atrigger frame comprising a field having a value indicating a resolutionwith which at least one other device is allowed to reduce a bandwidth ofan allocated resource unit (RU) for transmitting data via acommunication channel; and transmit, via the communication channel, thetrigger frame to the at least one other device, wherein the at least oneother device is configured to transmit a second frame according to thevalue in the field indicating the resolution with which the at least oneother device is allowed to reduce the bandwidth.
 19. The circuitry ofclaim 18, wherein the second frame is an uplink (UL) orthogonalfrequency division multiple access (OFDMA) frame.
 20. The circuitry ofclaim 18, wherein the trigger frame indicates one or more sub-bandlocations in which the bandwidth is allowed to be reduced.